diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/testing/selftests/bpf/cgroup_helpers.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/bpf/cgroup_helpers.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c new file mode 100644 index 000000000..033051717 --- /dev/null +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <sched.h> +#include <sys/mount.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <linux/limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <linux/sched.h> +#include <fcntl.h> +#include <unistd.h> +#include <ftw.h> + + +#include "cgroup_helpers.h" + +/* + * To avoid relying on the system setup, when setup_cgroup_env is called + * we create a new mount namespace, and cgroup namespace. The cgroup2 + * root is mounted at CGROUP_MOUNT_PATH + * + * Unfortunately, most people don't have cgroupv2 enabled at this point in time. + * It's easier to create our own mount namespace and manage it ourselves. + * + * We assume /mnt exists. + */ + +#define WALK_FD_LIMIT 16 +#define CGROUP_MOUNT_PATH "/mnt" +#define CGROUP_WORK_DIR "/cgroup-test-work-dir" +#define format_cgroup_path(buf, path) \ + snprintf(buf, sizeof(buf), "%s%s%s", CGROUP_MOUNT_PATH, \ + CGROUP_WORK_DIR, path) + +/** + * enable_all_controllers() - Enable all available cgroup v2 controllers + * + * Enable all available cgroup v2 controllers in order to increase + * the code coverage. + * + * If successful, 0 is returned. + */ +static int enable_all_controllers(char *cgroup_path) +{ + char path[PATH_MAX + 1]; + char buf[PATH_MAX]; + char *c, *c2; + int fd, cfd; + ssize_t len; + + snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path); + fd = open(path, O_RDONLY); + if (fd < 0) { + log_err("Opening cgroup.controllers: %s", path); + return 1; + } + + len = read(fd, buf, sizeof(buf) - 1); + if (len < 0) { + close(fd); + log_err("Reading cgroup.controllers: %s", path); + return 1; + } + buf[len] = 0; + close(fd); + + /* No controllers available? We're probably on cgroup v1. */ + if (len == 0) + return 0; + + snprintf(path, sizeof(path), "%s/cgroup.subtree_control", cgroup_path); + cfd = open(path, O_RDWR); + if (cfd < 0) { + log_err("Opening cgroup.subtree_control: %s", path); + return 1; + } + + for (c = strtok_r(buf, " ", &c2); c; c = strtok_r(NULL, " ", &c2)) { + if (dprintf(cfd, "+%s\n", c) <= 0) { + log_err("Enabling controller %s: %s", c, path); + close(cfd); + return 1; + } + } + close(cfd); + return 0; +} + +/** + * setup_cgroup_environment() - Setup the cgroup environment + * + * After calling this function, cleanup_cgroup_environment should be called + * once testing is complete. + * + * This function will print an error to stderr and return 1 if it is unable + * to setup the cgroup environment. If setup is successful, 0 is returned. + */ +int setup_cgroup_environment(void) +{ + char cgroup_workdir[PATH_MAX - 24]; + + format_cgroup_path(cgroup_workdir, ""); + + if (unshare(CLONE_NEWNS)) { + log_err("unshare"); + return 1; + } + + if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL)) { + log_err("mount fakeroot"); + return 1; + } + + if (mount("none", CGROUP_MOUNT_PATH, "cgroup2", 0, NULL) && errno != EBUSY) { + log_err("mount cgroup2"); + return 1; + } + + /* Cleanup existing failed runs, now that the environment is setup */ + cleanup_cgroup_environment(); + + if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) { + log_err("mkdir cgroup work dir"); + return 1; + } + + if (enable_all_controllers(cgroup_workdir)) + return 1; + + return 0; +} + +static int nftwfunc(const char *filename, const struct stat *statptr, + int fileflags, struct FTW *pfwt) +{ + if ((fileflags & FTW_D) && rmdir(filename)) + log_err("Removing cgroup: %s", filename); + return 0; +} + + +static int join_cgroup_from_top(char *cgroup_path) +{ + char cgroup_procs_path[PATH_MAX + 1]; + pid_t pid = getpid(); + int fd, rc = 0; + + snprintf(cgroup_procs_path, sizeof(cgroup_procs_path), + "%s/cgroup.procs", cgroup_path); + + fd = open(cgroup_procs_path, O_WRONLY); + if (fd < 0) { + log_err("Opening Cgroup Procs: %s", cgroup_procs_path); + return 1; + } + + if (dprintf(fd, "%d\n", pid) < 0) { + log_err("Joining Cgroup"); + rc = 1; + } + + close(fd); + return rc; +} + +/** + * join_cgroup() - Join a cgroup + * @path: The cgroup path, relative to the workdir, to join + * + * This function expects a cgroup to already be created, relative to the cgroup + * work dir, and it joins it. For example, passing "/my-cgroup" as the path + * would actually put the calling process into the cgroup + * "/cgroup-test-work-dir/my-cgroup" + * + * On success, it returns 0, otherwise on failure it returns 1. + */ +int join_cgroup(const char *path) +{ + char cgroup_path[PATH_MAX + 1]; + + format_cgroup_path(cgroup_path, path); + return join_cgroup_from_top(cgroup_path); +} + +/** + * cleanup_cgroup_environment() - Cleanup Cgroup Testing Environment + * + * This is an idempotent function to delete all temporary cgroups that + * have been created during the test, including the cgroup testing work + * directory. + * + * At call time, it moves the calling process to the root cgroup, and then + * runs the deletion process. It is idempotent, and should not fail, unless + * a process is lingering. + * + * On failure, it will print an error to stderr, and try to continue. + */ +void cleanup_cgroup_environment(void) +{ + char cgroup_workdir[PATH_MAX + 1]; + + format_cgroup_path(cgroup_workdir, ""); + join_cgroup_from_top(CGROUP_MOUNT_PATH); + nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT); +} + +/** + * create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD + * @path: The cgroup path, relative to the workdir, to join + * + * This function creates a cgroup under the top level workdir and returns the + * file descriptor. It is idempotent. + * + * On success, it returns the file descriptor. On failure it returns -1. + * If there is a failure, it prints the error to stderr. + */ +int create_and_get_cgroup(const char *path) +{ + char cgroup_path[PATH_MAX + 1]; + int fd; + + format_cgroup_path(cgroup_path, path); + if (mkdir(cgroup_path, 0777) && errno != EEXIST) { + log_err("mkdiring cgroup %s .. %s", path, cgroup_path); + return -1; + } + + fd = open(cgroup_path, O_RDONLY); + if (fd < 0) { + log_err("Opening Cgroup"); + return -1; + } + + return fd; +} + +/** + * get_cgroup_id() - Get cgroup id for a particular cgroup path + * @path: The cgroup path, relative to the workdir, to join + * + * On success, it returns the cgroup id. On failure it returns 0, + * which is an invalid cgroup id. + * If there is a failure, it prints the error to stderr. + */ +unsigned long long get_cgroup_id(const char *path) +{ + int dirfd, err, flags, mount_id, fhsize; + union { + unsigned long long cgid; + unsigned char raw_bytes[8]; + } id; + char cgroup_workdir[PATH_MAX + 1]; + struct file_handle *fhp, *fhp2; + unsigned long long ret = 0; + + format_cgroup_path(cgroup_workdir, path); + + dirfd = AT_FDCWD; + flags = 0; + fhsize = sizeof(*fhp); + fhp = calloc(1, fhsize); + if (!fhp) { + log_err("calloc"); + return 0; + } + err = name_to_handle_at(dirfd, cgroup_workdir, fhp, &mount_id, flags); + if (err >= 0 || fhp->handle_bytes != 8) { + log_err("name_to_handle_at"); + goto free_mem; + } + + fhsize = sizeof(struct file_handle) + fhp->handle_bytes; + fhp2 = realloc(fhp, fhsize); + if (!fhp2) { + log_err("realloc"); + goto free_mem; + } + err = name_to_handle_at(dirfd, cgroup_workdir, fhp2, &mount_id, flags); + fhp = fhp2; + if (err < 0) { + log_err("name_to_handle_at"); + goto free_mem; + } + + memcpy(id.raw_bytes, fhp->f_handle, 8); + ret = id.cgid; + +free_mem: + free(fhp); + return ret; +} + +int cgroup_setup_and_join(const char *path) { + int cg_fd; + + if (setup_cgroup_environment()) { + fprintf(stderr, "Failed to setup cgroup environment\n"); + return -EINVAL; + } + + cg_fd = create_and_get_cgroup(path); + if (cg_fd < 0) { + fprintf(stderr, "Failed to create test cgroup\n"); + cleanup_cgroup_environment(); + return cg_fd; + } + + if (join_cgroup(path)) { + fprintf(stderr, "Failed to join cgroup\n"); + cleanup_cgroup_environment(); + return -EINVAL; + } + return cg_fd; +} |